Substrate inspection apparatus, substrate inspection method and method of manufacturing semiconductor device

Abstract

A substrate inspection apparatus includes: an electron beam irradiation device which emits an electron beam and causes the electron beam to irradiate a substrate to be inspected as a primary beam; an electron beam detector which detects at least one of a secondary electron, a reflected electron and a backscattered electron that are generated from the substrate that has been irradiated by the electron beam, and which outputs a signal that forms a one-dimensional or two-dimensional image of a surface of the substrate; a mapping projection optical system which causes imaging of at least one of the secondary electron, the reflected electron and the backscattered electron on the electron beam detector as a secondary beam; and an electromagnetic wave irradiation device which generates an electromagnetic wave and causes the electromagnetic wave to irradiate a location on the surface of the substrate at which the secondary beam is generated.

1. A substrate inspection apparatus comprising:
 at least one electron beam irradiation device which emits at least one electron beam and causes the at least one electron beam to irradiate a surface of a substrate having a first member and a second member which are formed thereon, a material of the first member being an insulator and a material of the second member being different from the material of the first member, a potential of the first member being initially positive with respect to the second member, thereby a potential difference occurs in an area to be inspected in the surface of the substrate; 
 an electron beam detector which detects at least one of a secondary electron, a reflected electron and a backscattered electron that are generated from the substrate which has been irradiated by the electron beam and which outputs a signal that forms a one-dimensional or two-dimensional image of the surface of the substrate; 
 a mapping projection optical system which causes imaging of at least one of the secondary electron, the reflected electron and the backscattered electron on said electron beam detector; and 
 a first electron beam irradiation condition controller which controls said at least one electron beam irradiation device to cause said at least one electron beam to irradiate the surface of the substrate under an irradiation condition to reduce the potential difference in the area to be inspected, 
 wherein said irradiation condition includes a condition to make the first member negatively charged. 
 
   
   
     2. The substrate inspection apparatus according to  claim 1 ,
 wherein said condition to make the first member negatively charged is a condition in which a total secondary electron emission ratio is less than 1, said total secondary electron emission ratio being a ratio of a total quantity of the secondary electron, the reflected electron and the backscattered electron with respect to a quantity of electrons incident on the substrate. 
 
   
   
     3. The substrate inspection apparatus according to  claim 1 ,
 wherein the substrate further has a third member and a fourth member which are formed thereon, a material of the third member being a metal and a material of the fourth member being a semiconductor, and 
 said first electron beam irradiation condition controller controls a total current magnitude for the electron beam per unit surface area of the substrate or energy of the electron beam incident on the surface of the substrate in accordance with a layout pattern or electrical characteristics of at least of the first member, the second member and the third member. 
 
   
   
     4. The substrate inspection apparatus according to  claim 1 ,
 wherein said at least one electron beam irradiation device includes a first electron beam irradiation device and a second electron beam irradiation device and the at least one electron beam includes a first electron beam and a second electron beam, said first electron beam irradiation device emitting the first electron beam and causing the first electron beam to irradiate an area to be inspected in the surface of the substrate as a primary beam, and said second electron beam irradiation device emitting the second electron beam and causing the second electron beam to irradiate the area of the substrate to be inspected in the surface of the substrate prior to irradiation of the primary beam. 
 
   
   
     5. The substrate inspection apparatus according to  claim 4 , which further comprises a second electron beam irradiation condition controller,
 wherein said at least one electron beam irradiation device includes a third electron beam irradiation device and the at least one electron beam includes a third electron beam, the third electron beam irradiation device emitting the third electron beam and causing the third electron beam to irradiate the surface of the substrate prior to irradiation of the primary beam, and 
 said irradiation condition further includes a condition to make the first member positively charged, and the second electron beam irradiation condition controller controlling at least one of the second electron beam and the third electron beam under the irradiation condition to make the first member positively charged which has been made negatively charged to an excessive degree. 
 
   
   
     6. The substrate inspection apparatus according to  claim 5 ,
 wherein said irradiation condition to make the first member positively charged is a condition in which the total secondary electron emission ratio is more than 1. 
 
   
   
     7. The substrate inspection apparatus according to  claim 1  which further comprises a second electron beam irradiation condition controller,
 wherein said at least one electron beam irradiation device includes a first electron beam irradiation device and a second electron beam irradiation device and the at least one electron beam includes a first electron beam and a second electron beam, said first electron beam irradiation device emitting the first electron beam and causing the first electron beam to irradiate an area to be inspected in the surface of the substrate as a primary beam, and said second electron beam irradiation device emitting the second electron beam and causing the second electron beam to irradiate the area to be inspected in the surface of the substrate prior to irradiation of the primary beam, 
 said irradiation condition includes a condition to make the first member positively charged, and 
 the second electron beam irradiation condition controller controls the second electron beam device to cause the second electron beam to irradiate the surface of the substrate under the irradiation condition to make the first member positively charged which has been made negatively charged to an excessive degree by the irradiation of the primary beam. 
 
   
   
     8. A substrate inspection method comprising:
 emitting at least one electron beam and causing the at least one electron beam to irradiate a surface of a substrate having a first member and a second member which are formed thereon whereby at least one of a secondary electron, a reflected electron and a backscattered electron being generated from the substrate, a material of the first member being an insulator and a material of the second member being different from the material of the first member, the potential of the first member being initially positive with respect to the second member, thereby a potential difference occurs in an area to be inspected in the surface of the substrate; 
 projecting said at least one of a secondary electron, a reflected electron and the backscattered electron as a secondary beam to cause imaging of the secondary beam; 
 detecting an image caused by said imaging of the secondary beam and outputting a signal to form a one-dimensional or two-dimensional image of the surface of the substrate, and 
 a first electron beam irradiation condition control over said at least one electron beam causing said at least one electron beam to irradiate the surface of the substrate under an irradiation condition to reduce the potential difference in the area to be inspected, 
 wherein said irradiation condition includes a condition to make the first member negatively charged. 
 
   
   
     9. A substrate inspection apparatus comprising:
 an electron beam irradiation device which emits an electron beam and causes the electron beam to irradiate a substrate to be inspected as a primary beam; 
 an electron beam detector which detects a reflected electron among electrons generated from the substrate which has been irradiated by the primary beam, said reflected electron having an energy immediately after generation thereof substantially equivalent to an incident energy of the primary beam; 
 a mapping projection optical system which projects said reflected electron as a secondary beam and causes imaging of the secondary beam on said electron beam detector as an inspection image of one or two dimension; and 
 a controller which controls at least one of said electron beam irradiation device, said mapping projection optical system and said electron beam detector on the basis of at least one of a first estimated value and a second estimated value, said first estimated value being representative of an extent of distortion of the inspection image, and said second estimated value being representative of an extent of difference in contrast among materials in the inspection image when an area of the substrate to be inspected is constituted of a plurality of different materials. 
 
   
   
     10. The substrate inspection apparatus according to  claim 9 ,
 wherein said controller controls incident energy of the primary beam based on at least one of said first and second estimated values. 
 
   
   
     11. The substrate inspection apparatus according to  claim 9 , which further comprises a noise electron deflector to deflect a noise electron other than said reflected electron to prevent the noise electron from entering said electron beam detector. 
   
   
     12. The substrate inspection apparatus according to  claim 11 ,
 wherein a noise electron shield has a first electrode which excites a negative electric field to prevent passage of the noise electron therethrough. 
 
   
   
     13. The substrate inspection apparatus according to  claim 11 , which further comprises a noise electron trapper to trap the noise electron which is prevented from entering said electron beam detector. 
   
   
     14. The substrate inspection apparatus according to  claim 13 ,
 wherein said noise electron trapper has a second electrode to which a positive voltage is to be applied. 
 
   
   
     15. A substrate inspection method comprising:
 emitting an electron beam and causing the electron beam to irradiate a substrate to be inspected as a primary beam; 
 projecting a reflected electron among electrons generated from the substrate which has been irradiated by the primary beam, as a secondary beam to cause imaging of the secondary beam to an inspection image of one or two dimensions, said reflected electron having an energy immediately after generation thereof substantially equivalent to an incident energy of the primary beam; 
 detecting said reflected electron at said imaging of the secondary beam to output a signal to form the inspection image of one or two dimensions; and 
 controlling at least one of the irradiation of the primary beam, a trajectory of the secondary beam and the detection of the electrons on the basis of at least one of a first estimated value and a second estimated value, said first estimated value being representative of an extent of distortion of the inspection image, said second estimated value being representative of an extent of difference in contrast among materials in the inspection image when an area of the substrate to be inspected is constituted of a plurality of different materials.